A child-proof closure of this type is known from the GB-A-2 035 279. This known closure involves a housing which can be placed over a screw cap and which is provided with a locking device which, when at rest; grips under the edge of the screw cap or under the projecting edge of the neck of the bottle, which housing is freely rotatable on the neck in this state. The housing of this closure is provided with a quiver-like part which offers room to a finger of the hand and which is provided at the bottom with an actuating device for the lock, with the aid of which the lock can be moved against spring force and can be brought to the unlocked state. Said locking device is located at a distance from the opening of the quiver-like part which is larger than the average length of the longest finger of a child of a predeterminable age and can therefore be reached only by a finger having a predeterminable minimum length, such as a finger of the hand of an adult. Children of the abovementioned age or younger are therefore unable to unlock the closure. The correct distance or length can be determined on the basis of statistical data on the sizes of the people in the field of application.
If it is desired to use the contents of a bottle protected in this manner, the housing of the closure has to be removed, after which the screw cap is accessible and can be screwed off in the normal manner. This may be a screw cap which is protected by means of a break strip. However, after being opened once, this last type behaves like a normal screw cap. If the closure is placed on the screw cap, the latter is freely rotatable therein, with the result that it is not possible to unscrew the screw cap with the aid of the housing of this closure.
This known child-proof closure is not always safe. The person who has taken some of the contents of the bottle in order to make it inaccessible again for children, may be interrupted in doing so and there is then a danger that said person does not bring about the restoration of the closure again in due time because, to do this, it is first necessary to find and place the screw cap and then to find and place the housing with the lock.
The object of the invention is to provide a child-proof closure which lacks the drawbacks of the known closure, which can if necessary be brought into the protected closed state with one flick of the hand and which, in addition, can be completely sealed for transportation purposes even after any opening and pouring out, without replacing any component such as the closure cap with retainer ring and break strips. In addition, the object of the invention is a child-proof closure which, after the contents of a bottle have been poured out, can be transferred to a subsequent bottle.